Description of the Plan (Details) - Retirement Savings Plan	12 Months Ended
Dec. 31, 2025 USD ($) h loan Year	Dec. 31, 2024 USD ($)
EBP, Description of Plan [Line Items]
Percentage of operating profit	15.00%
Compensation to investment alternatives, percentage	100.00%
Hours of service required \| h	1,000
Minimum annual compensation percentage	1.00%
Maximum annual compensation, percentage	50.00%
Employer contribution, matching percentage	100.00%
Participant compensation matched, percentage	9.30%
Tax-deferred contributions	3.00%
Contribution withdrawl period, new employee	90 days
Assumed retirement age \| Year	65
Forfeited nonvested account	$ 4,636,044	$ 13,882,000
Maximum borrowing amount	$ 50,000
Number of loans outstanding per participant \| loan	1
Retirement age	59 years 6 months
EBP, Employer Matching Contribution
EBP, Description of Plan [Line Items]
Employer contribution vesting percentage	20.00%
EBP, Contribution Vesting Less Than Five Year
EBP, Description of Plan [Line Items]
Employer contribution vesting service period	5 years
EBP, Contribution Vesting, Participant With 1000 Hours
EBP, Description of Plan [Line Items]
Employer contribution vesting service period	1 year
EBP, Retirement Age
EBP, Description of Plan [Line Items]
Employer contribution vesting percentage	100.00%

EBP, Employer Contribution, Percentage Of Operating Profit

No definition available.

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- Definition

EBP, Employer Contribution, Retirement Age

+ References

No definition available.

+ Details

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- Definition

EBP, Employer Contribution Vesting Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	luv_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Employer Contribution Vesting Service Period

+ References

No definition available.

+ Details

Name:	luv_EBPEmployerContributionVestingServicePeriod
Namespace Prefix:	luv_
Data Type:	xbrli:durationItemType
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- Definition

EBP, Note Receivable From Participant, Account, Number Of Loans Outstanding Per Participant

+ References

No definition available.

+ Details

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Namespace Prefix:	luv_
Data Type:	xbrli:integerItemType
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Period Type:	duration

- Definition

EBP, Participant Contribution, Annual Compensation to Investment Alternatives, Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	luv_
Data Type:	dtr-types:percentItemType
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Period Type:	duration

- Definition

EBP, Participant Contribution, Contribution Withdrawl Period, New Employee

+ References

No definition available.

+ Details

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Namespace Prefix:	luv_
Data Type:	xbrli:durationItemType
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Period Type:	instant

- Definition

EBP, Participant Contribution, Hours Of Service Required

+ References

No definition available.

+ Details

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Namespace Prefix:	luv_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

EBP, Participant Contribution, Pretax, Minimum Annual Compensation To Total Compensation, Percentage

+ References

No definition available.

+ Details

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Namespace Prefix:	luv_
Data Type:	dtr-types:percentItemType
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Period Type:	duration

- Definition

EBP, Retirement Age

+ References

No definition available.

+ Details

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Namespace Prefix:	luv_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer matching contribution on eligible participant contribution to employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

Name:	us-gaap-ebp_EmployeeBenefitPlanEmployerContributionMatchingPercentage
Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of participant compensation eligible for employer matching contribution for participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of plan asset, in forfeited nonvested account, no longer allocated to participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 962
-SubTopic 325
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478873/962-325-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 962
-SubTopic 205
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478416/962-205-50-1

+ Details

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Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of maximum account balance that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)) can borrow.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of eligible compensation contributed for participant automatically enrolled in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)).

+ References

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Percentage of maximum pretax annual compensation that participant in employee stock purchase, saving, or similar plan (employee benefit plan (EBP)), is permitted to contribute to total pretax annual compensation.

+ References

+ Details

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- Details

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- Details

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- Details

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- Details

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- Details

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